


A Mermaid's Heart

by Kalira



Series: Where the Crimson Lion Calls Home [2]
Category: Voltron: Legendary Defender
Genre: Alternate Universe - Supernatural Creatures, M/M, Mermaid Allura (Voltron), Mermaid Shiro (Voltron), Mermaids, Pirate Captain Keith, Pirates, Rescue, Sheith Month 2018, Sky Pirates, Trust, attempted drowning
Language: English
Status: Completed
Published: 2018-07-01
Updated: 2018-07-01
Packaged: 2019-05-29 23:48:30
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,570
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15084416
Author URL: https://archiveofourown.org/users/Kalira/pseuds/Kalira
Summary: Captain Keith has been captured by a pirate hunter who, frustrated with his noncompliance, intends to have a little fun with his execution.





	A Mermaid's Heart

**Author's Note:**

> Written for Day 1 of [Sheith Month](https://sheithmonth.tumblr.com/): Trust.
> 
> Such a broad prompt and so fitting for them. . . I wasn't sure what I wanted to go with until this 'verse popped up to take over.

Keith growled and kicked against the ropes tightening around his legs as he was thrown to the deck beneath the cold eyes of the privateer captain. He would have spat an insult, but he’d been gagged after the first few, just before he’d been tied tighter and kicked down the stairs to be locked in the brig.

Captain Stein smirked at him. “I know all about you, rabid little _cur_ of a _pirate_. Captain _Keith_ , who flies an airship and calls a _mermaid_ . . . _lover_.”

Keith’s eyes narrowed, fury lighting in his veins at the ugly tone.

“You put your trust in such a _monster_ , do you?” Stein asked. It wasn’t the first time he’d asked questions of Keith, but he’d given up getting actual _answers_ two days ago, only shortly after capturing him, and no longer had his gag removed when he spoke to Keith, resorting to nothing more than taunts and insults.

Keith glared, growling through the gag wedging his jaw wide.

“No need to posture! Your crew _abandoned_ you, after all.” Stein smirked at him. “No need to put on a brave face or try and uphold any . . . _honour_.” The sneer made it quite clear what Stein thought of that, honourless wretch that _he_ was.

Keith’s eyes narrowed, the gag hiding the tick of a smile. Keith had ordered his crew to go as soon as he realised the trap closing in on them, get back to the ship and _get in the air_ , and the only one caught had been him.

“So there’s no need to hold up that brace façade. You don’t _really_ trust that _creature_ , do you? I’ve little idea what you thought you could get out of it,” Stein shook his head, still sneering, “surely you aren’t such a fool as to believe the tales of the gifts awaiting the one who wins a mermaid’s _love_ ; but there’s no need to pretend for _my_ sake.”

Keith growled again, muscles tensing as he fought the bonds holding him only to give up again quickly. He’d already tested and retested them, to the point of wearing himself out. There was no give - he wouldn’t be getting free that way.

“Well, if you’re so determined, let’s see how you fare, then.” Stein smirked again.

Keith stilled, searching the privateer captain’s face for a clue as to _what_ he meant.

“I’ll wager you’ll last . . . what, fifteen minutes before they shred and bleed you?” Stein said with a laugh. “Haul him up and _throw him overboard_. We’re in mermaid waters now, after all.” Another laugh and a broad gesture towards the railing. “See how your _love_ fares against what mermaids truly are, _Captain Keith_.”

Keith struggled as several pairs of hands caught hold of him, but he wasn’t able to do much more than make it difficult for them, knocking the wind out of at least one of the men. They still got him up and dragged him to the side of the ship, the ocean lapping at the wood far below.

“Goodbye . . . little _Captain_.”

Keith barely had a moment to take in the condescending words before he was flying, tumbling through the air with no ability to affect his own trajectory. He plummeted towards the water, he didn’t even know _where_ \- he’d been kept in the brig as they left behind the port city where he’d been captured.

He twisted again as he neared the water, and caught sight of a familiar rock formation.

Keith took a breath an instant before he hit the water, plunging deep with a shock of cool saltwater rushing over him. He sank quickly, but didn’t struggle - he was bound too tightly to swim, he could only tire himself out and use up the very limited oxygen he had. And he knew where he _was_ , now. Not only _mermaid waters_ , he was near the treacherous currents that ran over the Arus Trench.

He was nearly at the sandy bottom, a starfish scurrying out from beneath him, before something cool and strong wrapped around one of his forearms, arresting his momentum.

Keith lifted his head, twisting, and met a clear pair of shimmery grey eyes. Shiro looked worried, curling his tail around Keith and raising his hands to tear neatly at the cloth shoved into his mouth. “Keith!” he cried, his voice echoing oddly under the water to Keith’s ears.

Keith’s vision was spotty and dark - he could hold his breath for longer than most humans he knew, but he was rapidly reaching his limits. Shiro cupped his face in strong hands and brought their mouths together, breathing a surprising influx of air into his lungs and making him nearly choke, head spinning.

The ropes binding him fell free a few moments later and Keith clenched his jaw against the impulse to gasp as feeling rushed back into places that had been too tightly bound. He clung to Shiro, head jerking as he saw a shimmering flash of pink ghost past them on one side.

It was out of sight quickly, and Shiro drew his attention back, hands smoothing over Keith’s sides and tail uncoiling from around his legs. Shiro wrapped his arms around Keith’s waist and tucked him close, tail giving a powerful stroke and pushing them upwards, rapidly driving them back to the surface.

Keith sputtered as they came up into the air, crumpling into his lover’s support. Shiro chirred to him, tail waving gently below them and then curling up to stroke his broad tail fin along Keith’s hip and legs before returning for another slow stroke. He kept them both steady easily, his arms strong and sure around Keith.

Keith took a few minutes to cough and catch his breath and then just to _breathe_. Shiro was reassuringly solid, his heartbeat a too-rapid thrum against Keith’s ribs. His heart was beating too fast even for him, and Keith realised-

Of course. Keith leaned into Shiro a little more, resting his brow against his lover’s cheek. Of course he would have been frightened for Keith, seeing him bound and sinking. He took an experimental deeper breath, mouth open, and when it came smoothly he nudged his nose against Shiro’s jaw and tried for words.

“Thank you, precious.” Keith said, his voice a little rough but clear enough to understand.

“Are you really all right?” Shiro asked, smoothing one hand up and down Keith’s back.

Before Keith could respond there was an echoing boom of splintering wood amidst a great splash, and he jumped, twisting in Shiro’s arms. He looked back towards the ship he had been captured aboard and-

Keith’s eyes widened as he watched another powerful wave _surge_ even higher over the ship and crash down upon it, already broken in two and shedding more boards and great chunks of the decks all the time. A flash of pink and a sharp cry and Keith’s eye tracked Queen Allura as she raised her hands, the slashes of bright colour over her wrists and face glowing.

The ship groaned and twisted, _crunching_ inwards, and sinking rapidly below the surface.

Queen Allura tossed her hair back and flicked her tail, turning her back entirely on the sinking ship - Keith saw no one at the surface; had they _all_ been drawn to the depths with the ship?

Keith swallowed, shaking his head slightly. “Your Queen is a little terrifying, precious.” he said quietly.

Shiro rubbed his back again, kissing Keith’s cheek.

“Yes, I’m- I’m all right, thanks to you.” Keith said, wrapping his arms over Shiro’s shoulders. “All my crew got away, didn’t they?”

Shiro sighed, looking a little sad, but nodded.

“They did, Captain.” Queen Allura said from near his shoulder, and Keith turned to look at her. “Pidge was quite insistent on going looking for you, I believe your ship will be somewhere about here soon enough.”

Keith snorted, lips tugging into a smile. “Thank you, your majesty.” He bowed his head to her, and she smiled in return.

“It was my pleasure to assist you, Captain.” Queen Allura said genteelly. She looked past him at Shiro, her smile gentling even further. “All is well, Shiro.” she said quietly, brushing a hand over Shiro’s shoulder and swimming an almost lazy circuit around them as she passed.

Keith nodded, meeting his lover’s eyes again. He smoothed one hand over the ball of Shiro’s shoulder, then curled his fingers and rubbed his knuckles up and down Shiro’s arm, feeling the bunched muscle supporting him.

“Thank you, Allura.” Shiro said quietly, and she gave a smile over her shoulder, brilliant eyes sharp and fathomless as the sea. Then she turned and dove under the surface, a flick of her tail fin at the surface the last sign of her before she was gone.

Keith stroked Shiro’s face, fingers shaking slightly with exhaustion. “I love you, precious.” he said softly, leaning in for a light brush of a kiss.

Shiro’s arms tightened around Keith’s waist. “I love you too, baby.” He drew Keith into another kiss, careful but much needier.

 _I know_ , Keith thought, bringing a hand up to cradle Shiro’s jaw as he returned the kiss. He knew and trusted in Shiro’s heart with all the strength of his own and it was only pure ignorance and foolishness that would have anyone thinking either was false, or shakeable.

Keith smiled against his lover’s mouth, hand sliding down Shiro’s neck, just behind his delicate gills.

**Author's Note:**

> I can also be found on [Tumblr](https://kalira9.tumblr.com/).


End file.
